Filter for a Plasma Plume

Abstract

A filter for a pulsed laser deposition device includes a housing with two pass-through openings arranged in the housing wall and forming a pass-through channel for passing at least part of the plasma plume through the housing, which pass-through channel extends from one side of the housing to an opposite side of the housing, at least one primary blade arranged at a distance from and rotatable around a rotation axis, with the path of the at least one primary blade intersecting with the pass-through channel and with the at least one primary blade having a contact surface for contact with the plasma plume, and a drain channel connecting to a drain opening arranged in the housing wall.

Claims

1. A filter for filtering particles from a plasma plume, the filter comprising: a housing comprising a housing wall and two pass-through openings arranged in the housing wall to form a pass-through channel for passing at least part of the plasma plume through the housing, which pass-through channel extends from one side of the housing to an opposite side of the housing; at least one primary blade arranged within the housing at a distance from and rotatable around a rotation axis, wherein a path of the at least one primary blade intersects with the pass-through channel and wherein the at least one primary blade has a contact surface for contact with the plasma plume; and a drain channel connecting to a drain opening arranged in the housing wall, wherein the housing wall is configured to direct particles contacted by the contact surface of the at least one primary blade toward the drain opening.

2. The filter according to claim 1, wherein the contact surface comprises a concave shape facing in a rotation direction of the at least one primary blade.

3. The filter according to claim 2, wherein a cord line of a radial cross section of the contact surface makes an angle larger than 15 degrees with the rotation axis.

4. The filter according to claim 1, further comprising a disc arranged in the housing, the disc comprising at least one pass-through opening arranged in the disc.

5. The filter according to claim 4, wherein the at least one primary blade is arranged on the disc.

6. The filter according to claim 5, wherein the at least one primary blade is arranged adjacent to and trailing, when viewed in a rotation direction of the disc, the at least one pass-through opening in the disc.

7. The filter according to claim 5, wherein a cylindrical wall is arranged on the disc and concentrically with the rotation axis, and wherein the at least one primary blade connects to the cylindrical wall.

8. The filter according to claim 1, further comprising a secondary blade arranged to be rotatable around the rotation axis and to trail the at least one primary blade in a direction of rotation about the rotation axis.

9. The filter according to claim 8, wherein an angle between a longitudinal axis of the at least one primary blade and a radial line extending from the rotation axis to a proximal end of the at least one primary blade is smaller than an angle between a longitudinal axis of the secondary blade and a radial line extending from the rotation axis to a proximal end of the secondary blade.

10. The filter according to claim 1, further comprising a plurality of auxiliary blades arranged at a distance from and rotatable around the rotation axis.

11. The filter according to claim 9, further comprising an auxiliary drain channel connecting to an auxiliary drain opening arranged in the housing wall.

12. A pulsed laser deposition device configured to transfer material from a target to a substrate by pulsed laser deposition, the pulsed laser deposition device comprising: a laser; and a filter for filtering particles from a plasma plume, the filter comprising a housing comprising a housing wall and two pass-through openings arranged in the housing wall to form a pass-through channel for passing at least part of the plasma plume through the housing, which pass-through channel extends from one side of the housing to an opposite side of the housing; at least one primary blade arranged within the housing at a distance from and rotatable around a rotation axis, wherein a path of the at least one primary blade intersects with the pass-through channel and wherein the at least one primary blade has a contact surface for contact with the plasma plume; and a drain channel connecting to a drain opening arranged in the housing wall, wherein the housing wall is configured to direct particles contacted by the contact surface of the at least one primary blade toward the drain opening.

13. The pulsed laser deposition device according to claim 12, wherein the contact surface comprises a concave shape facing in a rotation direction of the at least one primary blade.

14. The pulsed laser deposition device according to claim 13, wherein a cord line of a radial cross section of the contact surface makes an angle larger than 15 degrees with the rotation axis.

15. The pulsed laser deposition device according to claim 12, wherein the rotation axis is a rotation axis of the at least one primary blade, further comprising a disc rotatable arranged in the housing, wherein a rotation axis of the disc coincides with the rotation axis of the at least one primary blade, and wherein at least one pass-through opening is arranged in the disc.

16. The pulsed laser deposition device according to claim 15, wherein the at least one primary blade is arranged on the disc.

17. The pulsed laser deposition device according to claim 16, wherein the at least one primary blade is arranged adjacent to and trailing, when viewed in the rotation direction of the disc, the at least one pass-through opening in the disc.

18. The pulsed laser deposition device according to claim 16, wherein a cylindrical wall is arranged on the disc and concentrically with the rotation axis, and wherein the at least one primary blade connects to the cylindrical wall.

19. The pulsed laser deposition device according to claim 12, further comprising a secondary blade arranged rotatable around the rotation axis and trailing the at least one primary blade in a direction of rotation about the rotation axis.

20. A method of filtering particles in a pulsed laser deposition device, comprising: directing a pulsed laser at a target to generate a plasma plume and particles; passing the plasma plume and the particles into a filter housing through a first pass-through opening of the filter housing; rotating at least one primary blade within the filer housing such that the at least one primary blade passes through a portion of the plasma plume comprising the particles; and directing the particles through a drain opening and a drain channel of the filter housing by bouncing the particles from the primary blade.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] These and other features of the invention will be elucidated in conjunction with the accompanying drawings.

[0032] FIG. 1 shows a schematic perspective view of an embodiment of a filter according to the invention arranged in a PLD device.

[0033] FIG. 2 shows a cross-sectional view along the line II-II in FIG. 1.

[0034] FIG. 3 shows a perspective view of the disc with blades of the filter according to FIG. 1.

[0035] FIG. 4 shows top cross-sectional view of the filter according to the invention in a first state.

[0036] FIG. 5 shows top cross-sectional view of the filter according to the invention in a second state.

[0037] FIGS. 6A and 6B show an axial top view and a cross-sectional radial view of the primary blade with a concave surface as shown in FIG. 5 on enlarged scale.

DESCRIPTION OF THE INVENTION

[0038] FIG. 1 shows a schematic view of an embodiment 1 of a filter according to the invention. The filter 1 has a housing 2 with a pass-through opening 3 at the top and a pass-through opening 4 at the bottom (see FIG. 2). The housing 2 is provided with a drain channel 5 and an auxiliary drain channel 6.

[0039] A target material 7 is arranged above the pass-through opening 3 of the filter 1. If a laser beam 8 is pulsed onto the target material 7, a plasma plume 9 will be generated.

[0040] This plasma plume 9 will enter the pass-through opening 3, where undesired particles are filtered, such that a filtered plasma plume 10 will exit the filter 1 through the pass-through opening 4. The filtered plasma plume 10 is then deposited onto a substrate 11.

[0041] As shown in FIG. 2, a disc 12 is arranged rotatably in the housing 2 of the filter 1. On top of the disc a primary blade with a concave surface 13 is provided adjacent to a pass-through opening 14, which allows passage of a plasma plume 9, when the pass-through opening 14 is aligned with the pass-through openings 3, 4 in the housing 2 and forming a pass-through channel with a center line 15.

[0042] When the plasma plume 9 passes through the formed pass-through channel, the primary blade with concave surface 13 with swipe through the last part of the plasma plume 9 and will bounce undesired particles in the direction D to the drain opening and the connected drain channel 5.

[0043] FIG. 3 shows a perspective view of the disc 12 rotatably arranged around the rotation axis 16 in the housing 2 of the filter 1.

[0044] The disc 12 is provided with two oppositely arranged pass-through openings 14, which are each trailed by a primary blade 13 having a concave surface. Just behind each primary blade 13, a secondary blade 17 is arranged to bounce off particles towards the drain channel 5, which particles are too slow to be hit by the primary blade 13. Furthermore, a number of auxiliary blades 18 are arranged on top of the disc 12.

[0045] A cylindrical wall 19 is arranged radially inside of the primary blades 13, secondary blades 17 and auxiliary blades 18 to provide together with the housing 2 a more confined space for the undesired particles of the plasma plume 9.

[0046] FIG. 4 shows a cross-sectional top view of the filter 1 of the invention.

[0047] The housing 2 has a drain opening 20, on which the drain channel 5 is connected. This drain opening 20 is arranged on a line 21 extending perpendicular from both the center line 15 of the pass-through channel and a radial line 22 extending from the rotation axis 16 through the center line 15 of the pass-through channel.

[0048] The housing 2 has also an auxiliary drain opening 23, on which the auxiliary drain channel 6 is connected. This drain opening 23 is arranged on a line 24 extending perpendicular from both the center line 15 of the pass-through channel and a radial line 22 extending from the rotation axis 16 through the center line 15 of the pass-through channel.

[0049] FIG. 5 shows again the cross-sectional top view of the filter 1 of the invention. From this FIG. 5 it is clear that the radial line 25 extending from the rotation axis 16 to the proximal end of the primary blade 13 makes an angle α1 with the longitudinal axis 26 of the primary blade.

[0050] The radial line 27 extending from the rotation axis 16 to the proximal end of the secondary blade 17 makes an angle α2 with the longitudinal axis 28 of the secondary blade 17.

[0051] The radial line 29 extending from the rotation axis 16 to the proximal end of the auxiliary blade 18 makes an angle α3 with the longitudinal axis 50 of the auxiliary blade 18.

[0052] As already described above, the primary blade 13 has a concave surface which fo-cuses the particles from the plasma plume 9 hit by the primary blade 13 in a bundle 51 towards the drain opening 20 and the drain channel 5.

[0053] Furthermore, a pressure difference is generated between the center of the filter 1, around the rotation axis 16 and the auxiliary drain channel 6, such that an airflow L is generated which flows from the center towards the outside of the housing 2 in order to maintain pressure within the housing.

[0054] FIGS. 6A and 6B show an axial top view and a cross-sectional radial view of the primary blade with a concave surface 13 as shown in FIG. 5 on enlarged scale.

[0055] The concave surface 13 is curved from the bottom edge 30 towards the top edge 31 of the concave surface 13 and also in radial direction.

[0056] The cord line 32 of the bottom edge 30 makes an angle α1 with the radial line 33, which intersects with the most inner edge of the cord line 32. The cord line 35 of the top edge 31 makes an angle β2 with the radial line 34, which intersects with the most inner edge of the cord line 32.

[0057] Both angles α1 and β2 are larger than 0° and preferably larger than 15°.

[0058] FIG. 6B shows a cross-sectional radial view of the concave surface 13. The cord line 36 makes an angle β3 with the rotation axis 16. Also this angle β3 is larger than 0° and preferably larger than 15°.